Hello Srinivas,
I am using RedHat 9 with its kernel
2.4.20-8 . When i make your program it compiled
successfully but i am getting following errors while i
insmod
insmod cf.o
cf.o: unresolved symbol sys_open
cf.o: unresolved symbol sys_write
regards,
linux_lover.
--- "Srinivas G." <srinivasg@xxxxxxxxxxxxxxxxxxxxx>
wrote:
> Dear All,
>
> I have gone through your mails. Based on those mail
> messages I have
> created a test module in the kernel to create a
> file. It was compiled
> fine with out any error messages and working fine.
>
> I am using Red Hat 7.3 with 2.4.18-3 kernel version.
> Please fine the
> code below.
>
> cre_fil.c
>
------------------------------------------------------------------
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <asm/fcntl.h> /* for O_WRONLY */
> #include <linux/syscall.h> /* for sys_ functions */
> #include <asm/uaccess.h> /* for set_fs(), get_fs()
> etc. */
> #include <linux/string.h> /* for string length */
> #include <linux/slab.h> /* for kmalloc */
>
> MODULE_LICENSE("GPL");
>
> typedef struct tagWRITE_TEST
> {
> unsigned long fd;
> unsigned long x;
>
> }WRITE_TEST, *PWRITE_TEST;
>
> PWRITE_TEST ptest;
>
> void SysPrint(char * pString, ...)
> {
> static char buff[1024];
> va_list ap;
>
> va_start(ap,pString);
> vsprintf((char *)buff, pString, ap);
> va_end(ap);
>
> sys_write(ptest->fd,(char *)buff,strlen(buff));
> }
>
> int init_module(void)
> {
>
> printk("<%s> invoked!\n",__FUNCTION__);
> printk("File Creation Testing in Kernel
> Module!\n");
>
> set_fs(get_ds());
>
> /* allocate the memory for structre */
> ptest =
> (PWRITE_TEST)kmalloc(sizeof(WRITE_TEST),GFP_KERNEL);
> if(ptest == NULL)
> {
> printk("Structure Memory Allocation Fails!\n");
> return -ENOMEM;
> }
>
> ptest->fd = sys_open("srcdebug.txt", O_CREAT |
> O_WRONLY, 644);
> if (ptest->fd == 0)
> {
> printk("File Creation Error!!!\n");
> return 1;
> }
>
> SysPrint("File Creation Testing in Kernel
> Module!\n");
> SysPrint("Srinivas Testing the File Creation\n");
>
> /* close the file here */
> sys_close(ptest->fd);
>
> return 0;
> }
>
> void cleanup_module(void)
> {
> printk("Good bye!\n");
>
> /* free the allocated memory */
> kfree(ptest);
>
> }
>
> Makefile
> ------------------------------------------------
> INCDIR=/usr/src/linux-2.4/include
>
> CFLAGS=-DMODULE -D__KERNEL__ -I$(INCDIR) -O2 -Wall
>
> OBJS=cre_fil.o
> TARGET=cf.o
>
> $(TARGET): $(OBJS)
> $(LD) -r -o $(TARGET) $(OBJS)
>
> clean:
> $(RM) -f $(TARGET) $(OBJS)
>
>
------------------------------------------------------------------------
> --
>
> I need some information. Where can I get the
> information for sys_create,
> sys_write, sys_read, set_fs, get_fs, get_ds etc
> calls?
>
> Please provide any links which are related to that
> calls or any books.
>
> Thanks and regards,
> Srinivas G
>
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